Screw-threading machine



Patented Feb. 29, 1944 scnEw-rnnmnmc MACHINE Werner Plagemann and Wilhelm Wemhiiner, Berlin, Germany: vested in the Alien Property Custodian Application February 23, 1940, Serial No. 32!,472 In Germany March 2, 1939 2 Claims. ((31. 80-6) Our invention relates to improvements in screw-threading machinesand more particularly in screw-threading machines of the type comprising roller dies formed with similar screw threads and mounted one beside the other with their axes parallel and adapted to receive a blank to be threaded between the same, the said roller dies being rotated in the same direction and pressed transversely into engagement with the blank for sinking a thread therein. One of the objects of the improvements is to provide a screw-threading machine of this type by means of which threads may be sunk in the blank at spaced parts of the length thereof, and with this object in view my invention consists in providing rolling members which are provided with screwthreaded portions spaced from each other in accordance with the position of the threads to be produced on the blanks. Other objects of the improvements will appear from the following description.

For the purpose of explaining the invention an example embodying the same has been shown in the accompanying drawings in which the same reference characters have been used in all the views to indicate corresponding parts. In said drawings I Fig. l is an elevation showing the machine,

Fig. 2 is a top plan view of Fig. 1,

Fig. 3 is an elevation partly in section showing one of the rolling members and the mechanism for imparting rotary movement thereto.

Fig. 4 is an elevation showing a device for supporting the blank in position between the dies, and

Fig. 5 is an end elevation of Fig. 4.

The screw-threading machine may have any known or preferred construction. In the figures we have shown a machine the main parts of which are similar to the machine shown in the copending application for patent of Wilhelm Wemhiiner and Werner Plagemann, Ser. No. 214,733, Patent No. 2,257,253, patented September 30, 1941, and in the following we shall briefly describe those parts of the machine which are necessary for an understanding of the operation thereof.

The machine comprises a frame I on which a plate I is mounted so that it may be turned about a vertical pivot bolt 3 fixed to the frame I, the said plate being fixed in position by means of screws 4 passed through lugs 5 rising from the frame I. On the said plate a housing 6 is mounted which provides a bearing for a shaft 7 and a worm gearing 8 keyed thereto. At its forward end the said plate carries a guide way 9 in which a bearing member II is slldable, the said bearing member being adapted to be fixed in position by means of a screw H the head of which engages in a groove 12 made in the guide way On the frame I guide ways I4 are provided on which a slide II is guided which carries a housing Ii providing a bearing for a shaft I! and enclosing a worm gearing II. In a guide way 19 formed on the slide l5 and similar to the guide way 9 in which the slide 10 is mounted a slide 20 is mounted which is likewise fixed in position by means of a, screw 2|. The slides II and Ill provide end bearings for the shafts l and II.

The slide i5 is acted upon by two plungers 23 mounted in cylinders 24 having a supply of a fluid under pressure through pipes 25. The cylinders are fixed to a cross-head 26 rising from the frame I. To the slide l5 a tie rod 29 is secured which is passed through the cross-head 26 and carries a head 30 acted upon by a coiled spring 3|, the said spring urging the slide II- to the right when the supply of pressure fluid to the cylinders 24 is interrupted.

Transversely of the shaft'l and I1 shafts 5i and i2, 63 are mounted which carry worms 5, 55 meshing with the worm gears 8 and It, the said shafts being connected with a suitable source of power for imparting rotary movement to the shafts 1 and I1. The shaft 52, 53 is made in two telescoping sections permitting transverse movement of the slide l5 and the shaft I! carried thereby.

So far the machine is known in the art, with exception of the bearing members I! and 20.

In the construction shown in the aforesaid application of Wemhiiner and Plagemanna roller die is fixed to each of the shafts I and I1, and the said dies are provided with external screwthreads of the same pitch, and they are adapted to be rotated in the same direction for sinking a thread in a blank placed between the same. The machine shown herein is designed for forming screw threads at different parts of the length of the blank, such as is usual, for example, in staybolts which are formed with similar screwthreads at both ends, which screw-threads have the same pitch and form the continuation one of the other. By means of the improved machine such screw-threads may be sunk in the blank by one operation, and for this purpose the roller dies carried by the shafts 1 and I1 each have two threaded portions 34, 35 and 36, 31 the threads of which have the same pitch and are the continuation one of the other. Between the said threaded portions the dies have portions 38 which are reduced in diameter as compared to the threaded portions. In the preferred construction shown in the figures the roller dies are made in sections, viz. the dies or threaded portions II to I! and spacing sections 38, and the said sections are annular inshape and filed on the shafts 1 and II respectively, feather keys I! and key grooves 40 being provided for holding the said sections in position on the shafts l and ll. By thus composing the dies of sections we are enabled to manufacture only the threaded portions from high grade steel, while the spacing members may be made from'a less expensive material. Near their outer ends the shafts I and II are formed with screw-threaded portions 4| engaged by nuts 42 adapted to clamp the roller 'dies and spacing sections in position. In Fig. 2 we have shown roller dies the total length of which is such that the whole space available on the shafts I and I1 is occupied, the said length corresponding to stay-bolts of the greatest length to be threaded on the machine. If it is desired to thread shorter bolts spacing members I. or smaller lengths are filed on the shafts I and I1 and between the dies 34, II, II and 31, and in order to permit the said sections to be clamped together by the nuts 42 filling members 43 are filed on the shafts I and I1 between the dies 3!, l1 and the nuts 42 and between the dies 34, 36 and the housings 8 and It. It is preferred to provide a suitable number of spacing sections ll and filling members 43 which are selectively mounted on the shafts I and I1, so that staybolts of any desired length may be threaded, it being understood that the lengths of all the sections 38 are such that in each roller die the threads of the portions 34, II and 36, 31 are the continuation one of the other. Thus we are enabled to use the same clamping member for holding the parts of the dies together.

The dies may be readily exchanged by retracting the bearing members II and II from the guide ways I and II.

In the operation of the machine the blank I! is suitably supported from below so as to be held in the proper position between the roller dies, and as shown, the construction is such that the blank readily adapts itself to the desired position between the dies. For this purpose, the said sup- It will be understood that in our improved machine subsidiary devices are provided for controlling the operation, such as has been described in the said copending application of Wilhelm Wemhoner and Werner Plagemann. For example, at the end of the threading operation and when the thread has been sunk to the desired depth the machine is automatically thrown out of operation by adjustable electrical contacts provided on the free ends of the shafts 1 and I1.

We claim:

1. In a screw-threading machine comprising roller dies disposed one beside the other in spaced relation and formed with corresponding external screw-threads, means for rotating said roller dies in the same direction with a blank to be threaded between the same, and means to press said roller dies towards one another and into threading engagement with said blank, the herein described improvement, which consists in each of thesaid rollers dies having two axially spaced threaded portions and a non-threaded portion of reduced diameter between said threaded portions,

and blank supporting means comprising a grooved member mounted between the reduced portions of the dies, in which only the middle portion of the blank is slidably carried, and adapted to hold the blank in position between the said dies while the sets of co-operating adjacent threaded portions simultaneously complete two threads on opposite ends of the blank, respectively.

2. In a screw threading machine, the combination of a base; a journal on said base; a bearing member slidable relative to said journal and having a journal aligned with the first mentioned journal; a shaft rotatably mounted in said journals; a supporting member slidable on said base; a Journal on said supporting member; a bearing member slidable on said supporting member and having a journal aligned with the journal on the supporting member; a shaft rotatably mounted in the two last mentioned journals; means to rotate both of said shafts in the same direction; means to slide said supporting members; an annulus, formed integral with each of said shafts, adjacent the Journal on the base and the journal on the supporting member, respectively; a plurality of annular screw cutting dies slidable axially on each shaft; a plurality of spacer annuli slidable axially on each shaft; means to prevent relative rotation of the dies and the shaft on which they are mounted; and a nut threaded on each shaft adjacent the journals on the bearing members respectively, adapted to clamp the dies and annuli against the shaft annulus, to prevent displacement of the dies axially of the shaft during operation of the device.

WERNER PLAGEMANN. wmrmmr war/mom. 

